In color printing by using an image forming apparatus, such as a copying machine and a multi-functional peripheral (MFP), equipped with a color printing function, color management is one of keys to accurate reproduction of colors used in each page of a print job. In conventional color printing, color calibration includes measuring colors of a chart in which patches in CMYK colors are arranged, with a scanner or an in-line sensor disposed in an image forming apparatus; comparing color information of the color patches with the color information read with the scanner or in-line sensor to obtain the amount of color change; and performing feedback so as to put the amount of color change within a proper range.